personal memory agent

test(providers): pin nvattest executable bits to the real archives master

Ground truth is derived from the published archives through the repo's own extraction path, never from the authority. Member set, kind, and link target are already covered by the digest-pinned companion manifests, so this fixture covers only the executable bit. The offline check runs in make ci via make test, and the network-using generator is deliberately excluded from install-checks. Co-Authored-By: Codex <noreply@openai.com>